The present invention relates to devices and methods for manipulating and directing guidewires and other xe2x80x9crails,xe2x80x9d e.g. catheters, within the human vasculature, over or through which other devices are then introduced into the vasculature to perform a medical procedure.
In the field of vascular intervention, and more specifically in the field of interventional cardiology, devices known as guidewires are often used to facilitate access to a patient""s vascular system, placement of various devices and/or performance of certain procedures. A guidewire is maneuvered into place to act as a guide for positioning the placement of subsequent devices xe2x80x9cover the wire.xe2x80x9d The guidewire, typically ranging from 0.010xe2x80x3 to 0.038xe2x80x3 inch diameter, as compared to an interventional catheter which may range from 0.040xe2x80x3 to 0.25xe2x80x3 inch diameter, is extremely flexible and tracks easily into a patient""s vessels, allowing the physician to obtain an initial position, and many times to find the optimal position, in the vasculature prior to tracking a larger interventional catheter over the wire to perform an intervention. In addition, a guidewire may maintain access to a certain site in the vasculature should it be necessary for the physician to use multiple devices to perform an intervention at the site, or to perform multiple interventions at different sites in the vasculature.
Due to their flexibility, guidewire access minimizes trauma to the vessel being treated and assists in directing or guiding other devices through the curvature and tortuosity of the vascular system. Unwanted trauma may include xe2x80x9cskivingxe2x80x9d of the vessel, wherein a less flexible device may scrape the vessel wall at an undesired angle, and unintended perforation, wherein a device may be pushed through the vessel wall in an uncontrolled manner, leading to excessive bleeding (tamponade) and/or other severe patient complications.
Guidewires act as a rail over which other less flexible and larger diameter devices may be delivered safely, thereby reducing the risk of unwanted vessel trauma In current medical practice, guidewire access and performance of procedures xe2x80x9cover the wirexe2x80x9d are the preferred mode of vascular device delivery. As such, it is critical to the clinical acceptance of new devices and therapies for them to be compatible with this technique, and to be delivered over the wire.
In light of the development of certain clinical procedures, there is a need for devices and methods that more specifically direct, place and maintain a guidewire or other rail at one or more selected locations in the vasculature.
The present invention is directed to various devices and methods for achieving directed placement of guidewires or other flexible rails over which other catheters or other devices may be introduced to a targeted location. For example, the devices and methods of the present invention may be incorporated into novel clinical procedures, such as those disclosed in U.S. patent application Ser. Nos. 08/730,327, filed Oct. 11, 1996, 08/730,496, filed Oct. 11, 1996, and 08/970,694, filed Nov. 14, 1997, the disclosures of which are expressly incorporated herein by reference.
Several of these procedures are performed in an xe2x80x9cextravascularxe2x80x9d location (e.g., from vessel to vessel, from vessel to another structure, or from vessel to another location or space within the body), necessitating the positioning of guidewires outside the normal xe2x80x9cintraluminalxe2x80x9d location within the vessel itself. It may also be necessary to xe2x80x9corientxe2x80x9d the entrance and exit of guidewires between vessels to better control the angle of placement of subsequently placed devices.
Further, in the case where multiple devices are tracked over the wire subsequent to initial placement, it may be necessary to stabilize the wire within the vessel or other location to minimize potential vessel trauma due to multiple manipulations of subsequently placed devices. Also it may be necessary to minimize potential loss of placement of the guidewire should it become displaced in response to forces exerted on it by catheters as they are advanced or removed from the vessel.
In one aspect of the present invention, devices are provided for directing a guidewire, catheter or other rail substantially laterally with respect to a body passage within which the device is introduced. In a first preferred embodiment, the device includes an elongate member having proximal and distal ends, having a distal portion adapted for insertion within a body passage, and defining a longitudinal axis and an outer peripheral surface. A lumen extends between the proximal end and a peripheral opening in the distal portion, and a deflecting member is provided therein adjacent to the peripheral opening for directing a guidewire device substantially laterally with respect to the longitudinal axis.
Preferably, the deflecting member has a predetermined acute deflection angle for directing the guidewire device substantially distally and laterally. Alternatively, the deflecting member may have a predetermined oblique deflection angle for directing the guidewire device substantially proximally and laterally. In a preferred form, the guidewire device is a needle assembly having a guidewire lumen extending therethrough, although alternatively, the guidewire device may simply be a guidewire alone, which may be deflected substantially laterally when it contacts the deflection member and is advanced through the peripheral opening. In addition, the device may include an imaging and/or orientation element on the distal portion, such as a radiopaque marker, having a predetermined relationship with the peripheral opening.
In a second preferred embodiment, a catheter is provided for directing a guidewire substantially laterally with respect to a body passage within which the catheter is introduced. The catheter is an elongate member having proximal and distal ends, having a distal portion adapted for insertion within a body passage, and defining a longitudinal axis and an outer peripheral surface. A first lumen extends between the proximal end and a first axial opening in the distal end, and a second lumen extends between the proximal end and a second lateral opening in the distal portion proximate the distal end.
Preferably, the second lateral opening is located on the peripheral surface of the elongate member, and the second lumen includes a deflection ramp therein adjacent to the second lateral opening. In addition, the distal portion may include an angled step tapering to a distal tip, the second lateral opening being located on the angled step.
In another aspect of the present invention, devices are provided for releasably snaring a guidewire or other rail, e.g., to facilitate placement or manipulation of the guidewire. In a preferred embodiment, the snaring device includes an elongate member having proximal and distal portions, and having first and second lumens extending between the proximal and distal portions. The first lumen has a first distal opening proximate to a second distal opening of the second lumen on the distal portion.
A snaring member including a loop on its distal end is slidably received in the first lumen, the loop extending distally from the first distal opening and surrounding the distal portion of the elongate member such that the snaring member may be directed proximally and distally, the loop thereby substantially engaging and disengaging, respectively, an outer surface of the distal portion of the elongate member.
The loop may be biased to assume an enlarged substantially circular configuration, the substantially circular configuration preferably defining a predetermined diameter corresponding to a diameter of a lumen of a blood vessel. The corresponding distal portion of the elongate member has a diameter substantially smaller than the predetermined diameter. Preferably, the distal portion includes an angled step tapering to a distal tip, the first distal opening being located on the angled step, and the second distal opening being located on the distal tip.
In an alternative form, the snaring device includes an elongate member having proximal and distal ends, having a distal portion adapted for insertion within a body passage, and defining a longitudinal axis and an outer peripheral surface. A lumen extends between the proximal end and a peripheral opening in the distal portion. A snaring member is deployable substantially laterally from the peripheral opening, and includes a snare on its distal end, which may be retractable within a lumen in the snaring member, or otherwise adapted for releasably securing a guidewire device to the snaring member.
In another preferred embodiment, a system including cooperating end effectors is provided for placing and/or directing guidewire devices with respect to adjacent body passages, e.g., through an interstitial channel between two adjacent blood vessels. The system includes an elongate guidewire device having a substantially flexible distal portion having a size adapted for insertion within a blood vessel, and a directing member having a proximal end and a distal end having a size adapted for insertion within a blood vessel. The directing member defines a longitudinal axis, and has a portion that is directable substantially laterally with respect to the longitudinal axis, for example by providing a distal portion of the directing member having a precurved shape.
Cooperating end effectors are provided on the distal portion of the guidewire device and the distal end of the directing member for detachably securing the distal portion of the guidewire device and the distal end of the directing member together. In one form, the end effectors may include a magnet on the guidewire device and/or the directing member. Alternatively, the directing member may include a mechanical grasping mechanism, such as cooperating jaws or an expandable basket structure.
In another form, the end effectors may include a tip with a recess therein on one of the guidewire device or the directing member, and a loop and pin on the other of the guidewire device or the directing member. The loop defines an aperture adapted to receive the tip therethrough, the pin being deployable within the aperture to detachably engage the recess.
In still another form, the directing member may be a catheter device having at least one lumen extending between the proximal and distal ends thereof. An end effector may be deployable from the distal end of the directing member through the at least one lumen. The end effector on the guidewire device may be an enlarged distal tip to facilitate capture by the catheter device. For example, the end effector on the catheter device may be a snare including a loop adapted to receive the enlarged distal tip on the guidewire device therethrough.
The snare may be deployed through a single lumen in the catheter device, or alternatively, the catheter device may include first and second lumens. The snare may then include a looped wire having first and second ends which extend proximally through the first and second lumens, respectively, to define an enclosed loop extending beyond the distal end. Alternatively, the snare may be a basket assembly expandable between contracted and enlarged conditions.
The devices and systems according to the present invention may be used in a variety of procedures for directing, snaring and/or manipulating one or more guidewires, catheters or other rails between two locations within one or more body passages. For example, in accordance with the present invention, a method is provided for directing an elongate guidewire device between two body passages connected by an interstitial channel, preferably between two blood vessels within the coronary system. A guidewire device may be advanced along a first vessel to a location adjacent to an interstitial channel communicating with a second vessel. A snaring member may be advanced along the second vessel and through the interstitial channel into the first vessel.
A distal end of the guidewire device may be snared, captured or otherwise releasably coupled to the snaring member, and the snaring member may be withdrawn through the interstitial channel back into the second vessel, thereby pulling the distal end of the guidewire device into the second vessel. The distal end of the guidewire device may then be released from the snaring member within the second vessel. Before releasing the distal end of the guidewire device, the snaring member may also be directed along the second vessel to a predetermined location.
In another method according to the present invention, a guidewire may be placed in a predetermined orientation between two blood vessels within a patient""s body, preferably between a vein and an artery, more preferably between a coronary vein and a coronary artery. A distal end of a first guidewire may be advanced distally from a first percutaneous entry site into a first vessel adjacent a proximal channel between the first vessel and a second vessel. A snaring member may be advanced from a second percutaneous entry site distally into the second vessel adjacent the proximal channel.
The distal end of the first guidewire or the snaring member may be advanced through the proximal channel, and the distal end of the first guidewire may be snared with, or otherwise coupled to, the snaring member. The snaring member may be withdrawn proximally from the second vessel and out the second entry site, thereby xe2x80x9cflossingxe2x80x9d the first guidewire through the first and second vessels between the first and second entry sites.
A catheter may be advanced from the second entry site over the flossed first guidewire into the second vessel adjacent the proximal channel, and a snaring member advanced from the first entry site into the first vessel. A second guidewire may be deployed from the catheter, and either the catheter, the second guidewire or the snaring member advanced through the proximal channel. A distal end of the second guidewire may be snared with the snaring member, and then the snaring member may be directed proximally or distally along the first vessel to a selected location. The distal end of the second guidewire may be released from the snaring member at the selected location.
Preferably, the selected location is a distal location in the second vessel, and the snaring member is advanced through a distal channel from the first vessel into the second vessel to advance the second guidewire into the distal location in the second vessel. The snaring member may be advanced through the distal channel over a fourth guidewire previously placed from the first entry site through the first vessel and the distal channel into the distal location in the second vessel. Thus, the second guidewire may facilitate a procedure to bypass a lesion in the second vessel at a location between the proximal and distal channels.
The devices and methods of the present invention may facilitate directed placement of guidewires or other flexible rails within a patient""s body over which other catheters or interventional devices may be introduced. One or more guidewire directing catheters and/or one or more snaring devices for grasping or capturing guidewires may be used in a variety of procedures to achieve desired control and placement of the guidewires. Thus, unlike conventional snaring devices, which substantially permanently snare guidewires for removal from a patient""s body, the devices and methods of the present invention facilitate xe2x80x9creversibility,xe2x80x9d i.e., the ability to selectively snare, direct and release rails within a patient""s body.
Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.